A device for displaying information (i.e., display device), for example television or monitor for PC, is an indispensable in the information society in recent years.
Display type of the display device can be largely categorized into three types of reflective type, transmission type, and light emission type. Generally, in manufacturing the display device, a person who manufactures the display device selects preferable display type depending on the environment for the display device.
However, in recent years, portability of the display device has been enhanced by miniaturization and thin film formation of the display device, so that a mobile display device has often been used under the environment of different brightnesses. Thus, even in such environment, it is required that the display device have high performance for displaying information.
As techniques for a respond to the above requirement, for example display devices in which any of display types is combined with one another are disclosed below in patent references 1 to 3.